JPH0412646A - Immersed motor - Google Patents

Abstract

PURPOSE:To prevent the penetration of liquid by breath phenomena by providing a pipe, which communicates with the inside of a motor and has such a length that comes out of the liquid level, in the upper part of a housing whose inside is sealed, and inserting a cable for supplying the motor with power into the pipe. CONSTITUTION:The upper cover 21 of a pump unit is provided with a tapered threaded hole 28, and therein a pipe 71, whose lower part 72 is threaded and tapered and which communicates with inside of a motor 11 and has such a length that it comes out above the cover 14 of an oil tank 3, is screwed. Furthermore, a bushing 74 is screwed on the top of the pipe 71, and a bush 73 for sealing the pipe 71 and the cover 14 is installed between them. Moreover, a cable 75 for supplying the motor 11 with power is inserted in the pipe 71. Hereby, the penetration of liquid by breathing phenomena can be prevented, and the occurrence of explosion inside the motor can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an immersion type electric motor that is used by being immersed in a liquid.

[Prior Art and its Problems] Conventionally, hydraulic units have been used to generate hydraulic pressure.

In order to reduce noise generated by a hydraulic unit or to reduce the size of the hydraulic unit, a pump unit in which an electric motor and a pump are integrated is used by being immersed in pressure oil in an oil tank.

In conventional immersion type electric motors, the housing is constructed to be completely sealed to prevent oil from entering inside the motor. There was a problem with oil gradually accumulating inside the machine over many years of use.

In addition, if the motor is a completely sealed type like the conventional one, the pressure inside the motor changes due to temperature changes (so-called breathing phenomenon), so pressurized oil is likely to enter when the pressure decreases.

In such electric motors, if more than a certain amount of oil accumulates inside the motor, it will no longer rotate normally and must be replaced with a new one, resulting in a short lifespan.

There are also electric motors that are configured to rotate with the inside of the motor filled with oil from the beginning, but with this, the viscosity of the oil increases the resistance to rotation of the rotor, and the gap between the rotor and stator increases. Because it had to be made larger, slippage increased and the efficiency of the electric motor was low.

Furthermore, in an electric motor with such a configuration, if the temperature of the motor increases due to coil seizure or overload, there is a risk that the vaporized oil will ignite and explode. Because it burns for a long time, there was a risk of a major fire accident.

In view of the above-mentioned problem, the invention of claim 1 communicates the inside of the electric motor with the atmosphere to prevent liquid from entering due to breathing phenomenon,
The purpose of this invention is to provide a liquid immersion type electric motor that prevents an explosion inside the electric motor, and that even if an explosion occurs, there is no risk of a major accident.

It is an object of the invention of claim 2 to provide an efficient liquid immersion electric motor in which liquid does not accumulate inside the motor.

[Means to solve the problem]

In order to solve the above-mentioned problem, an immersion type electric motor according to the invention of claim 1 is an electric motor that has a housing whose inside is sealed and is used by being immersed in a liquid, and the upper part of the housing has a A long pipe is provided that communicates with the inside of the motor and extends upward from the liquid level, and an electric wire for supplying power to the motor is inserted through the pipe.

In the liquid immersion electric motor according to the invention of claim 2, the shaft of the electric motor protrudes downward, and a sole member is provided between the shaft and the housing to prevent liquid from entering from the outside. A threaded groove extending axially outward along the rotational direction of the shaft is provided on the axially inward side of the sealing member.

[For production]

The inside of the electric motor is connected to the atmosphere through a pipe.
Breathing phenomena also maintain pressure equilibrium between the inside and outside of the motor.

Power is supplied to and controlled by the electric motor by inserting electric wires or the like into the pipe.

The sealing member prevents liquid from entering the electric motor from the outside.

When a very small amount of liquid seeps into the shaft due to rotation of the shaft, the liquid is discharged to the outside along the thread groove as the shaft rotates.

At that time, since the sealing effect in the direction from the inside to the outside of the seal member is small, the seal member communicates with the rotation of the shaft and the discharge pressure from the thread groove, and the liquid is discharged.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 6 is a sectional front view of the hydraulic unit 1 according to the present invention.

The hydraulic unit 1 includes a casing 2 that covers the whole, an oil tank 3 housed in the casing 2, a valve device 4 for switching pressure oil and discharging it to the outside, and a pressure oil H inside the oil tank 3. The pump unit 5 includes a piping hose 6 that interconnects the valve device 4 and the boat of the pump unit 5, and the like.

The casing 2 consists of a cylindrical body 2a, a cover 2b covering the top, and a bottom 2c, which are connected to each other with screws. Sound absorbing materials 15, 15, . . . are attached to appropriate positions on the inner peripheral surface of the casing 2.

The oil tank 3 is removably attached to cover the tank body 13 whose bottom part is supported by support poles (17, 17) made of anti-vibration rubber, etc., and the top opening of the tank body 13. It consists of a lid body 14 that is closed. A drain valve 18 for draining drain and pressure oil H is attached to the bottom of the tank body 13.

The pump unit 5 includes an electric motor 11 and a pump 12 connected to the electric motor 11 and driven to rotate, which are integrally attached with bolts, and hanger bolts 16, 16 and 16 made of anti-vibration rubber or the like. It is suspended from the lid body 14 by...

FIG. 3 is a cross-sectional front view of the pump unit 5 according to the present invention;
FIG. 4 is a sectional front view showing essential parts of the pump unit 5 of FIG. 3, and FIG. 5 is a plan view of the pump unit 5 of FIG. 3.

Electric I! 11 is an upper cover 21, a lower cover 22, a cylinder 23, a stator 24 attached to the inner peripheral surface of the cylinder 23, a shaft 25, a rotor 26 attached to the shaft 25, a hair ring 27 that rotatably supports the shaft, and a discharge sole mechanism 2 that seals between the shaft 25 and the lower cover 22 and discharges accumulated oil.
It consists of 9 etc.

The connecting portions of the upper cover 21, the lower cover 22, and the cylinder 23 are sealed with gaskets such as O-rings, thereby forming a housing 20 that seals the inside of the electric motor 11.

FIG. 2 is a sectional front view showing the structure of an air venting device 70 provided in the electric motor 11 according to the present invention.

Referring also to FIG. 2, the upper cover 21 is provided with a tapered screw hole 28, and this screw hole 28 has a screw portion 72 that screws into the screw hole 28, and the electric motor 11 A pipe 71 having a length that communicates with the interior of the oil tank 3 and extends above the lid 14 of the oil tank 3 is connected by a screw portion.

The pipe 71 penetrates a hole provided in the lid body 14 and protrudes to the outside, and a bushing 74 is screwed into the upper end of the pipe 71. A bushing 73 is installed between the pipe 71 and the lid 14 to seal the space between them.

A 1M75 for supplying electric power to the electric motor 11 is inserted into the inside of the pipe 71.

Through this pipe 71, the inside of the electric motor 11 is communicated with the atmosphere and has atmospheric pressure, and electric power is supplied through the electric wire 75. Therefore, there is no need to separately provide piping for the electric wire 75 (the structure is simplified, and the labor and time required therefor can be saved).

FIG. 1 is a sectional front view of a discharge sole mechanism 29 provided in an electric motor according to the present invention.

In particular, with reference to FIGS. 1 and 4, a cylindrical liner 61 having a flange is fitted into a hole 63 provided in the center of the lower cover 22 in an interference fit state, and the liner On the lower side of 61 is a hole 6 which is also provided in the lower cover 22.
4, the sealing member 62 is fitted in an interference fit.

The liner 61 is made of metal or synthetic resin, and its inner diameter is slightly larger than the outer diameter of the shaft 25, with a clearance C of ten to several tens of microns provided therebetween. Furthermore, a threaded groove 64 is provided on the inner circumferential surface of the liner 61 and is threaded in a direction axially outward along the rotational direction of the shaft 25 .

The sealing member 62 includes a packing body 65 made of synthetic rubber or the like and having a substantially U-shaped cross section, a metal retainer 66 that supports the packing body 65, and an elastic ring 67 that presses the lip 65a of the packing body 65 against the outer peripheral surface of the shaft 25. Become.

The shaft 25 and the lower cover 22 are separated by the seal member 62.
Although the space between the shaft 25 and the shaft 25 is sealed to prevent oil from entering from the outside, since the shaft 25 rotates, it is not possible to completely prevent even the smallest amount of oil from leaking and entering.

Oil that has entered due to leakage accumulates around the shaft 25, but when the shaft 25 rotates, the oil
The oil adhering to the surface and surrounding oil is dragged by its viscosity and rotates.

Then, the oil flows into the threaded groove 64 provided in the liner 61.
1, pressure is generated in the oil accumulated on the back side of the lip 65a of the packing body 65. This discharge pressure causes the liner 5a to open slightly to allow outward flow, thereby discharging the oil to the outside of the motor 11.

In other words, the combination of the thread groove 64 and the shaft 25 acts as a type of pump, and this and the seal member 62
A discharge seal mechanism 29 is configured by the combination.

Note that at the beginning of use of the hydraulic unit 1, since the temperature is low and the viscosity of the oil is high, most of the oil accumulated inside the electric motor 11 is discharged at the beginning of operation.

Returning to FIG. 4, the pump 12 includes a front cover 31,
End cover 32, main body casing 33.2 outer rotors 34, 34.2 inner rotors 35, 35
, a center plate 36, a shaft portion 37 continuous from the shaft 25 of the electric motor 11, and the like.

The rotation of the shaft portion 37 causes the inner rotor 35 and the outer rotor 34 to rotate, and the pressure oil H discharged from the suction port 38 passes through the discharge port 39 to the lower cover 2 of the electric motor 11.
It is discharged from a discharge port 41 provided in 2 at a constant pressure. The above-mentioned piping hose 6 is connected to the discharge port 41, and discharged to the outside according to the switching operation of the valve device 4.

According to the pump unit 5 described above, the inside of the electric motor 11 is sealed by the housing 20 and communicated with the atmosphere by the air venting device 70.

Therefore, although the electric motor 11 is immersed in the pressure oil H in the oil tank 3, the pressure oil H does not enter the inside of the electric motor 11. In particular, if the motor is of a completely sealed type as in the past, the pressure inside the motor changes due to temperature changes, so pressure oil H is likely to enter when the pressure decreases, but in the motor 11 of this embodiment, Since the pipe 71 communicates with the atmosphere, the internal pressure of the electric motor 11 does not change even when such a breathing phenomenon occurs, and the pressure is balanced with the pressure (atmospheric pressure) applied to the pressure oil H. Intrusion is prevented.

Additionally, due to the rotation of the shaft 25, a very small amount of pressure oil H may leak from the knob member 62 and come in.
The oil thus accumulated is discharged to the outside along the thread groove 64 as the shaft 25 rotates, so that a large amount of oil does not accumulate inside the electric motor 11 to the extent that it affects the operation.

Therefore, even if the electric motor 11 is used for many years, the leaked oil will not gradually accumulate and interfere with the operation of the electric motor 11, and its lifespan will be long.

Furthermore, since the inside of the electric motor 11 is not filled with oil, the resistance to the rotation of the rotor 26 does not become large (and the gap between the rotor 26 and the stator 24 can be made small, so there is less slippage and the electric motor 11 No loss of efficiency.

Furthermore, with conventional electric motors that are filled with oil from the beginning, if the temperature of the motor increases due to coil seizure or overload, there is a risk that the vaporized oil will catch fire and explode. The housing will be destroyed and the filled oil will burn for a long time, which may lead to a major fire accident. On the other hand, in the electric motor 11 of this embodiment, the possibility of explosion is extremely low because oil does not accumulate, but even if an explosion were to occur,
Since the housing 20 is communicated with the atmosphere through the pipe 71, there is no danger of the housing 20 being destroyed, and since the amount of accumulated oil is small, it will be burned up in one explosion, and then it will burn for a long time. There is no risk of a major accident.

In the embodiments described above, the pitch, shape, number of threads, etc. of the thread grooves 64 can be changed in various ways. The shape, structure, material, etc. of the liner 61 and the seal member 62 can be changed in various ways. In addition, the structure, dimensions, number, materials, etc. of each part of the electric motor 11 and the pump unit 5 can be changed in various ways other than those described above.

[Effect of the invention] According to the invention of claim 1, the inside of the electric motor is communicated with the atmosphere to prevent liquid from entering due to breathing phenomenon, thereby preventing an explosion inside the electric motor and preventing an explosion from occurring in the event of an explosion. It is possible to use a liquid immersion type electric motor that does not cause a serious accident even in the event of an accident.

According to the second aspect of the invention, it is possible to provide an efficient liquid immersion electric motor in which liquid does not accumulate inside the motor.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional front view of a discharge seal mechanism provided in an electric motor according to the present invention, Fig. 2 is a cross-sectional front view showing the structure of an air vent device provided in an electric motor according to the present invention, and Fig. 3 is a cross-sectional front view showing the structure of an air vent device provided in an electric motor according to the present invention. FIG. 4 is a cross-sectional front view showing essential parts of the pump unit in FIG. 3, FIG. 5 is a plan view of the pump unit in FIG. 3, and FIG. 6 is a cross-sectional front view of the pump unit in accordance with the present invention. It is a sectional front view of a hydraulic unit. 11... Electric motor, 20... Housing, 25...
Shaft, 29... Discharge seal mechanism, 62... Seal member, 64... Thread groove, 70... Air venting device,
71...Pipe, 75...Electric wire, H...Pressure oil (liquid). Soyaft 5 Bonpunino II-Electric motor 12 Pump 20 Haunongt (Oil-immersed type bo/Buyunino (・) Diagram Diagram) 8 C

Claims (2)

[Claims] (1) An electric motor that has a housing that seals the inside and is used by being immersed in liquid, and the upper part of the housing has a long pipe that communicates with the inside of the electric motor and extends upward from the liquid level. An immersion type electric motor, wherein an electric wire for supplying electric power to the electric motor is inserted through the pipe. (2) The shaft of the electric motor protrudes downward, and a sealing member for preventing liquid from entering from the outside is provided between the shaft and the housing, and the sealing member is arranged axially inwardly of the sealing member. 2. The immersion type electric motor according to claim 1, wherein the immersion type electric motor is provided with a thread groove extending axially outward along the rotational direction of the shaft.